Is it possible for fry to have stunted growth?

Is it possible for fry to have stunted growth? Mickey platy fry. 3 Born in Feb. 2 still under 1/2 inch. 1 is the same size as our other adult. I haven't done anything different. I'm certain of birth date (and momma died giving birth )
Same tank, same food, same everything.

They haven't grown in months so I'm a little concerned something is wrong.

 

I think with some common tropicals inbreeding weakens the strain so much you get many stunted or deformed offspring.

 

When newborn fry are born, the biggest fry will begin to "emit" a horomone (or something) that stunts the growth of the other fry. That's why daily water changes are a must with fry, because it removes that horomone from the water. They'll grow, but it just takes a lot longer

 

Mwh7 will they continue to emit after 3-6+ months? They've always been in a community aquarium. While I didn't always change daily, I did change weekly or biweekly. We did have some ammonia spikes (minI cycles I guess), but these guys do seem tough even if small. These guys haven't grown a wink it seems since about month 2.

How much longer would it take for their growth to catch up?
(They pet store platy that reproduced, so ya...I'm sure inbreeding played a role).

 

Inbreeding is irrelevant to aquarium Platies. Growth is strictly controlled by three factors:

1. Space. This includes factors such as other tankmates. If you tried to raise them in a breeder net/box, they've been raised in the space of that confinement and will not grow normally. In a community tank they would be competing with adult fish for food. Particularly tricky, if they're not careful they may become food!

2. Water changes. They release GIS (Growth Inhibiting Secretions) their entire lives. Some people claim that there is no such thing, and that it is simply extra pollution (such as your ammonia spikes) from the number of fish that are present. However,up to the point where they sex out is when 80% of growth occurs, Massive daily water changes are the only way to get maximum growth.

3. Food. This is why fry should be given live foods. The constant presence of moving edibles stimulates their hunting instincts, and helps to maximize growth. Otherwise, you have to feed 2-10 times a day, depending on species, to get manufactured foods to them. Which is another reason for massive daily water changes.

I disagree with those who say their growth will "catch up". This can happen under some very specific circumstances, but generally once they show sexual maturity, growth is greatly slowed and they just don't live long enough to "catch up". This is why adults in the wild can vary greatly in size, as some get more food than others during the growth stage.

 

So in other words, chances are they will just stay this size? This was obviously our first batch of fry to actually live & not become food.

I know they have an adequate tank size (although I do agree we have some food competition going on for sure). Is it worth it to drop in an algae wafer or some frozen brine worms at this point? Usually we just do high quality flakes 2x/day.

Usually ammonia only spikes after we have a pet sitter. Normally it stays 0-0-<10. However, ph was all over when these guys where born. Gh/kh where messed up (too soft I think). Once I added some shells both numbers and ph are much better.

Oh, and on feeding...should I offer more times a day? The problem I'm running into is too much waste causing a spike. And the adults over feed causing that set of issues. So I've hesitated on that front.

Fwiw- we have 30 gal tank. 5 glo danios, 1 adult (male) platy, and the 3 "babies."

I have entertained some Cory cats to help with waste, but I don't have a sand substrate and don't really desire to change it out at the moment.

 

When newborn fry are born, the biggest fry will begin to "emit" a horomone (or something) that stunts the growth of the other fry. That's why daily water changes are a must with fry, because it removes that horomone from the water. They'll grow, but it just takes a lot longer

Just a question on this. Why is the one fish immune to the hormone that stunts the growth of the others?

This is from a thread on monster fish about inbreeding of platies. All of my breeding of fish has be accidential without assist from me so I not an expert on the subject. link to thread is included.

I do this on a semI commercial level. and ive found that the platy you are buying in the LFs are alrady pretty well interbred, I can in fact show you fish that are interbreed on a third generation that are tiny, and succeptable to illness. if you are serious about breeding these fish you could set up your own lines with only 4 tanks. I prefer to separate male and females at a young age and seel the males on to the shop and keep the females. if I'm ever at a fish shop I like to by platy that are oddly coloured. the problem ive had with trying to establish a new colourway of platy is that you need two similar fish from two souces to breed. its tough to do.

but good luck. I produce around 60 fish per month at the moment which I trade for tanks and food at my LFS. big cichlids eat lots of food

 

The person on Monsterfishkeepers isn't an expert on breeding livebearers, or even genetics in general. There are a lot of reasons for small platies, but genetics isn't one of them. I've been studying the genetics of fish for decades, and have discussed many of these matters with professional fish breeders.

I worked mostly with Swordtails. Platies actually have different requirements, which most people don't realize. Swords come from rivers and moving streams, often very fast water. Wild Platies come mostly from pools, often fairly stagnant pools, with a lot of plants. There is some adaptability in aquarium fish because most of the strains in the hobby are the result of hybridizing these two species, along with a few others thrown into the mix.

However, this genetic soup has also triggered a few bad combinations, which may or may not be in any given line. So yes, some problems can come from inbreeding, but most strains have had those bred out of them, oddly by inbreeding (more accurately, line breeding). So far as I am aware, small size is not the result of inbreeding, it is the result of inadequate care. Most people try to raise too many fry in too small a space, or they don't change enough water. Or they try to raise them on dry commercial foods, rather than giving them more nutritious frozen or live food.

The effect of GIS is greater on smaller fish. The largest fish is less effected, and as he grows, he gets more of the food, which may even include smaller siblings. This can be overcome by frequent water changes and more food that gets to all the fry. However, when an entire spawn stays small, the more likely cause is excess nitrogenous waste in the water from inadequate changes or excess food. It is a tightrope, and the larger the tank the wider the safe range.

 

Thanks for the explaination chrome, i've kept fish for years but never wanted to breed [culling seems necessary and something I don't want to do]. Interesting that platies and swords come from such different enviornments, they seem like the same fish [minus sword].

 

Genetics can affect fish size, though I agree poor care is the more likely determinant, especially if you're seeing significant size differences across few generations.

Platy habitats are variable. I've collected wild platies (X. variatus) in Mexico with some ichthyologist friends and they were found in calm pools in slowish rivers. In these particular areas, there were none to few plants and lots of rocks.

 

Wow collecting wild fish sounds like a great adventure. I remember reading Dr Axelrods collection trips in TFH magazine years ago and always wanted to do that. May have to add that to my bucket list.

 

@TexasDomer, That sounds like appropriate habitat for variatus, but not for maculatus. These are also two distinct species in the wild, but have been hybridized in captivity. I prefer to not refer to hobby Variatus as Platies because it can get confusing, though I'm certainly a minority in that practice.

From Freshwater Fishes of Mexico, by Robert Rush Miller (was finished by associates and published after his death):

Xiphophorus maculatus,(Gunther) Southern Platyfish

"Habitat: Prefers peripheral waters, such as ditches, ponds, backwaters, flooded pastures, and swamps, over muddy substrates among dense growths of aquatic plants; also common among roots and green vegetation beneath overhanging banks of major streams; currents typically none to weak but may be moderate along stream margins. Some habitats are sun drenched, others lie beneath a canopy of dense trees that inhibit penetration of direct sunlight. Water temperatures averaged 23-24 C in most places (Kallman 1975)."

 

@TexasDomer, That sounds like appropriate habitat for variatus, but not for maculatus. These are also two distinct species in the wild, but have been hybridized in captivity. I prefer to not refer to hobby Variatus as Platies because it can get confusing, though I'm certainly a minority in that practice.

From Freshwater Fishes of Mexico, by Robert Rush Miller (was finished by associates and published after his death):

Xiphophorus maculatus,(Gunther) Southern Platyfish

"Habitat: Prefers peripheral waters, such as ditches, ponds, backwaters, flooded pastures, and swamps, over muddy substrates among dense growths of aquatic plants; also common among roots and green vegetation beneath overhanging banks of major streams; currents typically none to weak but may be moderate along stream margins. Some habitats are sun drenched, others lie beneath a canopy of dense trees that inhibit penetration of direct sunlight. Water temperatures averaged 23-24 C in most places (Kallman 1975)."

Oh definitely agree! Different species have different habitats, etc. That was my experience for X. variatus in Hidalgo though. I think even the preferred habitat for X. variatus differs across its range.

What do you call X. variatus then? Just curious! The people I was sampling with referred to them as variatus platies, but we all know common names are terrible haha. I don't know how the bird people do it!

 

So....is there anything I can do at this point to try to promote better growth? Or are they just kinda stuck at this size.

 

I would separate the small fry to their own tank and feed 5-10 times a day. Live food plus whatever your feeding now. They may catch up.

 

You might still have a chance to get some normal growth out of them. They're not really all that old yet. The recommendations from jpm995 are about right, but don't forget frequent, large water changes.